AI 中文总结
研究利用多种光谱和显微镜方法，探究 Fe-12Cr 合金中 Cr 析出本质，与 Fe-9Cr 合金对比，发现 Cr 析出动力学、尺寸及密度差异，还首次报道了 Fe-(9, 12)Cr 合金无缺陷晶格的正电子寿命。
AI 中文摘要
Fe-Cr 二元合金是铁素体/马氏体钢的模型体系。Cr 聚集导致韧性损失，是使合金性能变差的影响因素之一，其严重程度取决于 Cr 浓度。本研究旨在通过正电子寿命谱、透射电子显微镜和穆斯堡尔谱研究，了解 Fe-12Cr 合金中 Cr 析出的本质，并与 Fe-9Cr 合金比较析出浓度和尺寸。发现从高温 FCC 相淬火的合金含有高密度位错和亚晶结构，在 748K 淬火后热处理时会导致富 Cr 的σ相析出，而无位错和亚晶结构的合金除晶界外无析出。选区衍射证实析出物是四方金属间σ相，与多数文献报道的富 Cr BCCα'相矛盾。穆斯堡尔谱研究表明基体其他部分有 Cr 贫化迹象，说明析出物比合金成分富 Cr。Fe-12Cr 合金中 Cr 析出动力学比 Fe-9Cr 合金高。Fe-12Cr 合金中析出物平均尺寸更高、数密度更低。此外，首次有充分证据报道了 Fe-(9, 12)Cr 合金无缺陷晶格中的实验正电子寿命。
英文摘要
The Fe-Cr binary alloy is a model system for ferrtitic/martensitic steels. Cr clustering instigated loss of ductility, is one of the influential factors to deteriorate the alloys, and its severity depends on Cr concentration. This study aims at understanding (i) the nature of Cr precipitation in Fe-12Cr alloy using positron lifetime spectroscopy, transmission electron microscopy and Mössbauer spectroscopy studies and (ii) comparing the precipitation concentration and size with respect to Fe-9Cr alloy. The quenched alloys (from the high temperature FCC phase) are found to contain a high density of dislocations along with the sub-grain structure which lead to Cr rich σ-phase precipitation during post-quenching heat treatment at 748 K, while the alloy prepared with no dislocations and the sub-grain structure shows no precipitation, except at grain boundaries, consistent with observations in Fe-9Cr alloys. Selected area diffraction confirmed that the precipitates are tetragonal intermetallic σ-phase, contradicting the majority of the literature on Fe-Cr ferritic alloys which reported it as Cr rich BCC α'-phase. Mossbauer spectroscopy studies showed signatures of Cr depletion from the rest of the matrix, indicating that the precipitates are Cr rich compared to the alloy composition. The kinetics of Cr precipitation is found to be higher in the Fe-12Cr alloy compared to the Fe-9Cr alloy. The average precipitate size is observed to be higher and the number density is lower in the Fe-12Cr alloy compared to the Fe-9Cr alloy. In addition, the experimental positron lifetime in defect-free lattice of Fe-(9, 12)Cr alloys is reported for the first time with substantial evidence.
CommentsJournal, 12 pages, 8 figures
